1. Field of the Invention
Embodiments of the invention relate to a method and apparatus for substrate treatment.
2. Description of the Related Art
Copper and its alloys are increasingly being used for metal interconnects in advanced integrated circuit fabrication because they have lower resistivities compared to aluminum. Copper can be deposited over high aspect ratio via and contact structures using metal electroplating. A typical electroplating method generally comprises vapor depositing a barrier layer over the via or contact, vapor depositing a conductive metal seed layer, e.g., copper, over the barrier layer, followed by electroplating a conductive metal over the seed layer to fill the via or contact structure. Finally, chemical mechanical polishing (CMP) can be used to define a planarized conductive interconnect feature by polishing the electroplated metal layer. Generally, CMP is preformed by providing relative motion between a substrate pressed against a polishing surface. A polishing fluid is provided between the substrate and polishing surface to chemically assist in the removal of material from the polished substrate surface. Some polishing fluid may additionally contain abrasives.
However, defects may be introduced into the planarized conductive layer after CMP. These defects may include, for example, particulate or chemical contamination, physical damage, discontinuity in the conductive layer, and so on. Therefore, the planarized metal layer is subjected to various post-CMP cleaning or treatment (e.g., thermal or plasma anneal) steps prior to additional processing such as subsequent deposition of a dielectric layer. However, even after post-CMP cleaning or treatment, problems may still be present in subsequent processing like continued vulnerability to chemical corrosion, or failure to provide a good adhesive surface for a subsequently deposited layer such as a dielectric layer.
Therefore, there is an ongoing need for improved systems for post-CMP treatment of metal layers, and also concomitant with CMP methods of treatment as well.
A system and method for treating a substrate following a chemical mechanical planarization process is generally provided. In one aspect, a system for treating a substrate generally includes a polisher, an annealing station and an optional deposition station. The polisher generally performs a chemical mechanical polishing process on the substrate. The deposition station generally forms a metal-containing layer on the substrate which is treated in the annealing station. In one embodiment, the deposition station and annealing station are disposed in a factory interface which is coupled to the polisher. The deposition station may optionally be incorporated into a cleaner residing within the factory interface. In another embodiment, the deposition station and annealing station are disposed on the polisher.
In another aspect of the invention, a method for treating a substrate generally includes chemical mechanical polishing the substrate, forming a metal-containing layer on the substrate and annealing the metal-containing layer.